Digital watermarks exist at a convergence point where creators and publishers of digitized multimedia content demand localized, secured identification and authentication of that content. Because piracy is clearly a disincentive to the digital distribution of copyrighted content, establishment of responsibility for copies and derivative copies of such works is invaluable. It is desirable to tie copyrights, ownership rights, purchaser information or some combination of these and related data into the content in such a manner that the content must undergo damage, and therefore reduction of its value, in order to remove such data for the purpose of subsequent, unauthorized distribution, commercial or otherwise. Legal precedent or attitudinal shifts recognizing the importance of digital watermarks as a necessary component of commercially-distributed content (audio, video, game, etc.) will further the development of acceptable parameters for the exchange of such content by the various parties engaged in such activities. These may include artists, engineers, studios, INTERNET access providers, publishers, agents, on-line service providers, aggregators of content for some form of electronic delivery, on-line retailers, individuals and other related parties that participate in the transfer of funds or arbitrate the actual delivery of content to intended recipients.
There are a number of hardware and software approaches that attempt to provide protection of multimedia content, including encryption, cryptographic containers, cryptographic envelopes or “cryptolopes,” and trusted systems in general. None of these systems places control of copyrights in the hands of the content creator as content is created. Further, none of these systems provide an economically feasible model for the content to be exchanged with its identification embedded within the signals that comprise the content. Given the existence of over 100 million personal computers and many more non-copyright-protected consumer electronic goods (such as audio clips, still pictures and videos), copyrights are most suitably placed within the digitized signals. Playing content is necessary to determine or “establish” its commercial value. Likewise, advertising and broadcast of samples or complete works reinforces demand for the content by making its existence known to market participants (via radio, television, print media or even the INTERNET).
Generally, encryption and cryptographic containers serve copyright holders as a means to protect data in transit between a publisher or distributor and the purchaser of the data. That is, a method of securing the delivery of copyrighted material from one location to another by using variations of public key cryptography or other cryptosystems. Cryptolopes are suited specifically for copyrighted text that is time sensitive, such as newspapers, where intellectual property rights and origin are made a permanent part of the file.
The basis for public key cryptography is provided, for example, in a number of patented inventions. Information on public-key cryptosystems can be obtained from U.S. Pat. No. 4,200,770 to Hellman et al., U.S. Pat. No. 4,218,582 to Hellman et al., U.S. Pat. No. 4,405,829 to Rivest et al., and U.S. Pat. No. 4,424,414 to Hellman et al. Digitally-sampled copyrighted material is a special case because of its long term value coupled with the ease and perfection in creating copies and transmitting by general purpose computing and telecommunications devices. In this special case of digitally-sampled material, there is no loss of quality in derivative works and no identifiable differences between one copy and any other subsequent copy.
For creators of content, distribution costs may be minimized with electronic transmission of copyrighted works. Unfortunately, seeking some form of informational or commercial return via electronic exchange is ill-advised, absent the establishment of responsibility of specific copies or instances of copies or some form of trusted system in general.